<html>
<head>
	<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
	<title>Document</title>
	<script type="text/javascript">
		function validate_required(field,alerttxt){
            with (field){
                if (value==null||value==""){
                	alert(alerttxt);return false
                }
                else {
                	return true
                }
            }
        }

		function validate_email(field,alerttxt){
			with(field){
				apos=value.indexOf("@")
				dotpos=value.lastIndexOf(".")
				if (apos<1||dotpos-apos<2) {
					alert(alerttxt);return false
				}
				else{
					return true
				}
			}
		}

		function validate_form(thisform){
			with(thisform){
				if (validate_required(email,"Email must be filled out!")==false) {
					email.focus();return false
				}
			}
		}
	</script>
</head>
<body>
	<form action="submitpage.htm"  onsubmit="return validate_form(this)" method="post">
		Email:
		<input type="text" name="email" size="30">
		<input type="submit" name="Submit">
	</form>
</body>
</html>